#A51D09 Color

#A51D09 is rgb(165, 29, 9) in RGB, hsl(8, 90%, 34%) in HSL, and about cmyk(0%, 82%, 95%, 35%) in CMYK. It has no registered color name of its own — the closest is Rufous (#A81C07), below the threshold most people can see at ΔE 1.9. White text is the more readable choice on this background.

#A51D09

HEX#A51D09

RGBrgb(165, 29, 9)

HSLhsl(8, 90%, 34%)

HSVhsv(8, 95%, 65%)

CMYKcmyk(0%, 82%, 95%, 35%)

OKLCHoklch(46.7% 0.173 31.3)

LABlab(36.50% 53.64 47.20)

LCHlch(36.50% 71.45 41.34)

What #A51D09 Is Called

Most hex codes have no name: there are 16.7 million of them and a few thousand registered names. These are the named colors nearest to #A51D09, ordered by CIE76 distance in CIELAB. Anything under about ΔE 2 is a difference most people cannot see.

Rufous#A81C07ΔE 1.9 OU Crimson Red#990000ΔE 4.77 Tomato Sauce#B21807ΔE 6.56 Mordant Red 19#AE0C00ΔE 7.76 Spartan Crimson#9E1316ΔE 8.49 Medium Red#B10304ΔE 8.69

Browse the full index of named colors A-Z or every red in the library.

#A51D09 Channel Values

How #A51D09 breaks down in each color model. Hue is measured in degrees around the color wheel; saturation, lightness, and the CMYK inks are percentages.

Model	Channels	Notes
RGB	R 165 · G 29 · B 9	8-bit channels as sent to the display
HSL	H 8° · S 90% · L 34%	Easiest model for building lighter and darker variants
HSV	H 8° · S 95% · V 65%	Matches the picker in most design tools
CMYK	C 0% · M 82% · Y 95% · K 35%	Approximate ink mix; confirm with an ICC profile before printing
Luminance	7.56:1 vs white · 2.78:1 vs black	WCAG 2.2 relative-luminance contrast ratios

Text Contrast & Accessibility

WCAG 2.2 contrast ratios for text on a #A51D09 background. AA requires 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Contrast is one check, not a full accessibility review.

TextWhite text7.56:1AA normal AA large AAA normal

Fails AABlack text2.78:1AA normal AA large AAA normal

Need a specific ratio against another background? Open #A51D09 in the contrast checker.

Colors That Go With #A51D09

Pairings derived from color-wheel relationships. The complementary color sits opposite #A51D09; analogous colors sit beside it; triadic and split-complementary sets spread evenly around the wheel. Select any swatch for its own breakdown.

Base

Complementary

Analogous

Analogous

Triadic

Triadic

Split comp.

Split comp.

Tints & Shades of #A51D09

Lighter tints and darker shades built by moving the lightness channel while holding hue and saturation, which is what you want for hover states, backgrounds, and text variants.

Tints

Shades

Want a full 50-950 ramp with semantic roles? Generate design tokens from #A51D09.

How #A51D09 Looks with Color Vision Deficiency

Simulated with the Viénot, Brettel & Mollon LMS projection model. Anomalous types are rendered as partial versions of the matching dichromacy, which is an approximation rather than a per-person clinical model.

Typical#A51D09

Protanopia#4D4D04

Protanomaly#7A3F06

Deuteranopia#666600

Deuteranomaly#845200

Tritanopia#A51B1B

Tritanomaly#A51C15

Achromatopsia#545454

Test a full palette in the color blindness simulator.

Using #A51D09 in Code

Copy-ready declarations for the places this color usually ends up.

CSS custom property--color-a51d09: #A51D09;

CSS backgroundbackground-color: #A51D09;

Tailwind configcolors: { 'color-a51d09': '#A51D09' }

SwiftUIColor(red: 0.647, green: 0.114, blue: 0.035)

Android XML<color name="color_a51d09">#A51D09</color>

SVG fillfill="#A51D09"

More Red Colors

#A51D09 sits in the red family. These are its neighbours across that family's full range, each with its own breakdown.

1f0000 fffafa 1f0005 fff5f5 1f0008 fff1f2 240000 fff1f0 240909 fff0f2 270707 ffedeb 4e0707 710f04 940000 a81c07 c0362c cdacac e30022 ee204d fa8072 ff1818 ff6467 ffb7c5

#A51D09 Frequently Asked Questions

What color is #A51D09?

#A51D09 is a dark red — rgb(165, 29, 9) in RGB and hsl(8, 90%, 34%) in HSL. It carries no registered color name of its own; the closest named color is Rufous (#A81C07), which is below the threshold most people can see at a CIE76 distance of 1.9.

What is the RGB value of #A51D09?

#A51D09 is rgb(165, 29, 9) — red 165, green 29, and blue 9 on the 0-255 scale.

What is the CMYK value of #A51D09?

#A51D09 converts to approximately cmyk(0%, 82%, 95%, 35%). CMYK output is a mathematical approximation for planning; confirm production print colors with your printer and ICC profile.

Should text on #A51D09 be black or white?

White text is the more readable choice. #A51D09 scores 7.56:1 against white and 2.78:1 against black, and WCAG 2.2 asks for at least 4.5:1 for normal body text.

Can I write #A51D09 as a CSS color keyword?

No. #A51D09 is not one of the CSS color keywords, so it has to be written as a hex, rgb() or hsl() value. The closest keyword is firebrick (#B22222) at a CIE76 distance of 9.16, which is clearly related but distinguishable side by side.

Open #A51D09 in a Tool

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Keep exploring: every red in the color library, the guide to shades of red, or the full color library.